<!DOCTYPE html>
<html>
<head>
  <title>2 double bounce</title>
  <style type="text/css">
    /*
 *  Usage:
 *
 *    <div class="sk-double-bounce">
 *      <div class="sk-child sk-double-bounce1"></div>
 *      <div class="sk-child sk-double-bounce2"></div>
 *    </div>
 *
 */
.sk-double-bounce {
  width: 40px;
  height: 40px;
  position: relative;
  margin: 40px auto; }
  .sk-double-bounce .sk-child {
    width: 100%;
    height: 100%;
    border-radius: 50%;
    background-color: #333;
    opacity: 0.6;
    position: absolute;
    top: 0;
    left: 0;
    -webkit-animation: sk-doubleBounce 2s infinite ease-in-out;
            animation: sk-doubleBounce 2s infinite ease-in-out; }
  .sk-double-bounce .sk-double-bounce2 {
    -webkit-animation-delay: -1.0s;
            animation-delay: -1.0s; }

@-webkit-keyframes sk-doubleBounce {
  0%, 100% {
    -webkit-transform: scale(0);
            transform: scale(0); }
  50% {
    -webkit-transform: scale(1);
            transform: scale(1); } }

@keyframes sk-doubleBounce {
  0%, 100% {
    -webkit-transform: scale(0);
            transform: scale(0); }
  50% {
    -webkit-transform: scale(1);
            transform: scale(1); } }

  </style>
</head>
<body>
 

    <div class="sk-double-bounce">
      <div class="sk-child sk-double-bounce1"></div>
      <div class="sk-child sk-double-bounce2"></div>
    </div>
</body>
</html>